Traditionally there are multiple people involved in the operation of a human assist exoskeleton, including the wearer, the controller, and the spotters. The idea is having more people aware and responsible for the exoskeleton's movement in attempt to keep the wearer of the exoskeleton from falling. Sometimes the wearer and the controller are the same person but this is not always the case.
When using an exoskeleton the wearer should be able to rapidly stop the test if they feel unsafe or uncomfortable. A manual push-button, separate from the exoskeleton and accessible by the human controller is often implemented in the design. Another power disconnect option is to physically unplug the exoskeleton via an external power cord. These methods have relied on a proactive action in order to stop operation.
This introduces a delayed reaction time into the disconnect procedure. In the event that the wearer feels a test needs to be stopped before it is apparent to the controller, there will be a delay in relaying the information from one person to the other. Additionally, the proactive action of pushing a button to stop power takes longer than a reactive action.
In other implementations, the wearer must hold a railing or similar device. The contact with the railing enables motion by closing a circuit. If the wearer lets go—i.e., breaks the circuit—power is interrupted and the exoskeleton ceases movement.